"rfs_read: attempt to read from non-file"

[Louis Marco]

We have a couple of dozen Suns and a single 386 running Interactive 3.2. I
have a file system physically on the Sun that's the file server mounted
via nfs on the 386 box.  Sometimes (not all the time, but often enough so
that I can't work the way I want) when I do an I/O intensive operation
such that the program is executing on the 386 but the data is read from
the Sun, the console on the (Sun) file server fills up with

rfs_read: attempt to read from non-file

messages.  What's particularly weird is we don't have rfs installed
anywhere.  (The string is from nfs_server.o).

If I run make on the source in the nfs-mounted directory, or copy a large
file from the nfs-mounted directory I eventually get the above.

	Why, and what should I do to make it stop?